If a substance is very alkaline/ basic, e.g. a pH of 14, does this mean that there are near to zero H+ ions (or it is possible to have such a situation where there are zero H+ ions and it is still alkaline) or does it mean there are lots of OH- ions relative to H+ ions? If so, how will this affect enzyme structure in very alkaline/ acidic conditions?

  • $\begingroup$ pH can go more than 14, also probably better off on chemistry $\endgroup$ Apr 16, 2018 at 20:48
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    $\begingroup$ I'm voting to close this question as off-topic because it is a chemistry question (see chemistry.SE) and not a biology question. $\endgroup$
    – Remi.b
    Apr 16, 2018 at 20:52
  • $\begingroup$ pH is most definitely a chemistry question. Acids and bases are chemistry, pH is crucial for many many chemical reactions that have absolutely nothing to do with biology. It's not much relevant to today how the idea initially spread. $\endgroup$
    – Bryan Krause
    Apr 17, 2018 at 0:21

1 Answer 1


This is a very chemical explanation. Here goes.

$\ce{pH = -log[H+]}$

$\ce{pOH = -log[OH-]}$

$\ce{pH + pOH = 14}$

Therefore, at a $\ce{pH}$ of $14$, $\ce{pOH}$ is zero, so there is 1 mole of $\ce{OH-}$ and $10^{-14}$ moles of $\ce{H+}$ in a liter of your substance.

  • $\begingroup$ Yes, in a simplistic model; although "in a mole of" should be "in a liter of". $\endgroup$ Apr 16, 2018 at 21:26
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    $\begingroup$ Please do not answer (or up vote) chemistry questions on biology.SE. Off-topic is off-topic. $\endgroup$
    – Remi.b
    Apr 16, 2018 at 21:44
  • $\begingroup$ I don't think it's too off-topic as he said something about enzymes at alkaline environments, but it doesn't seem like he researched a lot before hand, as the very definition of pH involves the concentration of H+. $\endgroup$
    – Inhibitor
    Apr 16, 2018 at 21:50

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